Squids Attract Bacteria By Their Slime

If you have ever been inquisitive about the vast variety of creatures living in the depths of the blue sea, you must have discovered a plethora of creatures living underwater. The salmon on your plate, great white sharks, octopuses and squids are among the thousands of organisms that live under the sea. Unlike terrestrial animals, aquatic life is very colorful and vibrant. This can be seen in the coral reefs, where a huge variety of creatures and plants of different sizes and features live. To experience this wonder, one can go to a clear water coral reef and do scuba diving and snorkeling there.

Few creatures on Earth are as interesting and unusual as fish. They have survived in an environment completely different from ours - in water that is often very dark and very deep, where sea life is sometimes a flashing, glowing, flickering show of lights. One of the phenomena commonly associated with aquatic life is bioluminescence. Most fish that live in the deepest depths are able to give off their own glow, a process called bioluminescence, and are known as the "glow in the dark fish." In fact in the sea, bioluminescence is everywhere - in fish, sea slugs, squid, jellyfish, and many other deep-sea dwellers.

It's the same process that causes a firefly to light up in the summer night. Almost all of marine bioluminescence are blue in color. There are two reasons for this: first, blue-green light travels furthest in the water; and second, most organisms are sensitive only to blue light - they lack visual ability to absorb longer red or shorter ultraviolet light. Bioluminescence is present in squids as well.

Young bobtail squids secrete the goo to attract light-emitting bacteria, which swim inside the squid and take up residence, helping it hide from predators. The bacteria make their own mucus made of polysaccharides. According to the scientists, the slimy goo is made by the bacteria by utilizing a particular gene called syp present in the bacteria. Baby bobtail squids are born without their bacterial partners, and must attract them from the surrounding seawater. Once inside the squid, the light-emitting bacteria enter narrow cavities.

During the daytime, squids lay in the sand, but at night they go out hunting in shallow coral reefs. When a squid is hunting in the moonlight, its dark silhouette would be visible to predators and prey from below, but the creature is camouflaged by its light-emitting partners. The amount of light emitted by the squid-dwelling bacteria usually matches the intensity of the moonlight. This helps camouflage the squid from hungry predatory fish.

Interestingly, a squid expels about 90 percent of its bacteria at dawn before burrowing into the sand! The remaining bacteria multiply during the day, and by the time the sun sets, the squid go hunting again with their luminescent partners.

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Sara Jones was a fine student but science was a source of frustration she didn't want her kids to suffer. She met Rick and Amanda Birmingham and realized their grasp of everyday science was the secret to making science fun. To learn more about the solution to science stress visit www.SuperFunScience.com